package web

import (
	"io/fs"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

func serveStatic(t *testing.T, target string, hdr map[string]string) *httptest.ResponseRecorder {
	t.Helper()
	sub, err := fs.Sub(staticFS, "static")
	if err != nil {
		t.Fatal(err)
	}
	h := http.StripPrefix("/static/", staticHandler(sub))
	req := httptest.NewRequest("GET", target, nil)
	for k, v := range hdr {
		req.Header.Set(k, v)
	}
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	return rec
}

// The whole point: a page's stylesheet link is content-addressed and cached for
// good, a bare URL revalidates, and revalidation costs a 304 rather than 90KB.
func TestStaticAssetsAreCacheable(t *testing.T) {
	versioned := assetURL("/static/css/output.css")
	if !strings.Contains(versioned, "?v=") {
		t.Fatalf("assetURL did not version the stylesheet: %q", versioned)
	}

	rec := serveStatic(t, versioned, nil)
	if rec.Code != 200 {
		t.Fatalf("versioned GET = %d, want 200", rec.Code)
	}
	if cc := rec.Header().Get("Cache-Control"); !strings.Contains(cc, "immutable") {
		t.Errorf("versioned Cache-Control = %q, want immutable", cc)
	}
	etag := rec.Header().Get("ETag")
	if etag == "" {
		t.Fatal("no ETag on a static asset")
	}

	rec = serveStatic(t, "/static/css/output.css", nil)
	if cc := rec.Header().Get("Cache-Control"); cc != "no-cache" {
		t.Errorf("bare Cache-Control = %q, want no-cache", cc)
	}

	// A stale page asking for a hash that no longer exists gets today's bytes,
	// but must not be told to keep them for a year under the old name.
	rec = serveStatic(t, "/static/css/output.css?v=000000000000", nil)
	if cc := rec.Header().Get("Cache-Control"); cc != "no-cache" {
		t.Errorf("stale-hash Cache-Control = %q, want no-cache", cc)
	}

	rec = serveStatic(t, "/static/css/output.css", map[string]string{"If-None-Match": etag})
	if rec.Code != http.StatusNotModified {
		t.Errorf("revalidation = %d, want 304", rec.Code)
	}
}

func TestAssetURLLeavesUnknownPathsAlone(t *testing.T) {
	if got := assetURL("/static/nope.js"); got != "/static/nope.js" {
		t.Errorf("assetURL(unknown) = %q, want it unchanged", got)
	}
}